Trouble Shooting

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• Trouble Shooting

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Troubleshooting Customer Generated Tooling
Problems
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The Most Common Customer Generated Tooling
Problems

• Broken or cracked punches, strippers and dies
• Galling
• Misalignment of punch and die
• Slug pulling
• Stripping problems
• Lock ring damage
• Broken or worn punch springs

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The Most Common Causes Of Tooling Problems

• Incorrect die clearance
• Incorrect sharpening methods
• Lack of tool maintenance
• Lack of sheet lubrication
• Tool size or station is not suited to the
  application
• Wear in the machines tool holder or keyway is
  causing alignment problems
• Tool holder in the machine is not adjusted
  properly, resulting in alignment problems

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Operator Checklist

• Right tool for the job (size and clearance)
• Are punch and die sharp ?
• Any wear on keys and alignment rings ?
• Orientation of punch and die in turret is correct
  ?

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Broken and Damaged Points

• CAUSES
• Incorrect die clearance
• Incorrect sharpening method
• Galling (too much heat)
• Not punching deep enough into the die (slug
  build-up in die)
• Point size too small relative to material
  thickness
• Incorrect punch/die alignment
• Slug pulling
• Camber in the sheet
• No corner radii on punch corners

chipped
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Cracked Punch Tip
Flats increased by bad grinding practices
Cantilever
Use correct shear geometry or move to larger
station.
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Sharpening Problems

• Undressed Wheel (black marks)
• Lack of Coolant
• Excessive Material Removal
• Wrong Grinding Wheel Choice

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Maximum slug
When punching in a Finn-Power D- Upforming
Station, the maximum Ø of the slug is reduced
from 78 to 53 mm !
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Part produced with correctly resharpened die
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Part produced with incorrectly resharpened die
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Broken Punch Retainer
Debris between punch and punch driver or
overtightening of draw bold can cause failure
(see catalog for Nm)
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Broken Strippers

• Look for indications on the stripper face that it
  has been hit, or for unusual marks or
  indentations.(e.g. slug on top of sheat)
• Also inspect the inside of the stripper for
  damage if none is evident on the outside
  surface.(punch ground off too much)

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Broken Strippers
Punch radius may hit stripper if the SBR is too
short. This will cause the stripper to break.
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Stripper maintenance
Remove debris in stripper it may cause guide
damage, sheet marking, etc.
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Broken or Cracked Dies

• Causes
• Uneven support of die in machine - dirt, debris
  or damaged shims under die
• Incorrect sharpening method
• Lack of corner radius
• Standard duty tool used in heavy-duty application
• Unnecessary keyways on slitting tools used in
  auto-index

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Crossed Punch and Die

• Severe damage to sheet, tooling, and machine may
  result from crossed punch and die.
• Operator should always visually or physically
  check tool orientation after installing tooling
  in the turret.

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Tool damage caused by poor storage or handling

• Dents, dings and scrapes can cause turret damage
  and damage to other tool components.
• Handle precision tooling carefully and store each
  item in a separate location to promote maximum
  tool life.

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Broken Die Adapters
10 ton maximum limitation for all die adapters
that step down one station.
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Galled Punches
Excessive heat, incorrect die clearance and lack
of lubrication are the most common causes

• Galled Punches cause
• Stripping problems
• Poor hole quality
• Accelerated tool wear

Galling (build-up) can be cleaned right after the
job is finished (when it is still warm) Cold
Galling can sometimes be removed. Nitride
treated or Maxima coated punches should be
considered. Reduce machine ram speed. Use sheet
lubrication and check die clearance.
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Misalignment-Punches
Uneven punch surface wear on any one side of the
tool (marking and or galling). More evident on
long, narrow shapes but can happen on any shape
or size tool.
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Misalignment of Dies
Damaged side has marks and abrasion, evidence of
being hit.
Undamaged side is sharp and has no evidence of
being hit.
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Misalignment Indicator Rat tail slug
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Sharpening Problems
Wave pattern on the die surface indicates a
grinding wheel that has not been dressed
properly. This causes heat that changes the
metallurgy of the material and accelerates tool
wear.
Coolant and correct coolant mix ratios must be
used. Dress wheel frequently to prevent heat
checking . Check grinding wheel for proper
hardness and grain size.
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Damaged die shims
Die shims need to be replaced when damaged and
need to be made from hardened shim stock or
purchased from Mate.
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Lock Ring Damage
Damaged locating key in machine can cause guide
damage.
Damage to locating key and lock ring keyway are
caused by incorrect tool loading procedure. To
prevent this damage, lower punch assembly slowly
into turret using T-handle tool.
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Spring Maintenance
Note Springs have a finite life and require
maintenance. Be aware of the different types of
springs used in Mates various tooling styles.
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Broken Disc Springs

• Disc springs require lubrication with EP grease.
• Stripping problems and spring sleeve damage can
  occur if springs are not maintained.
• If one disc spring is broken replace the entire
  stack.
• Maintain proper spring count and stack pattern.

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Application Problems
Cracked Spring retainer
12.7mm (1/2) thick material exceeds tool design
limits
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Application Problem Clamp and Form Clearing
Fully Guided Assemblies
Use only insert style punches with clamp clearing
strippers, or punch will hit stripper.
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Punching tough material
Punching in tough material like Hot Rolled Steel
? Following a monitored case at a Finn-Power
customer. After following this program the
customer achieved much better quality and
remarcable extension of tool life.
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Stripping forces
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Avoid problems Preventive maintenance
Remove punching debris from inside of guides,
strippers and punches.
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Trouble shooting summary
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Trouble shooting summary
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Trouble shooting summary
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Trouble shooting summary
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Thank you !
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